For Customer Community , we can use Sharing set or Sharing Group.

For Customer Community Plus & Partner Community we can use role & Sharing rule. Maximum role that community can have is 3 per account and thats limitation there as well.

Now , lets assume below scenario

Let’s assume, user Pat Stumuller wants to see either few or all Opportunity from Account Edge Communications. Point to note here – Org wide sharing default is private and Pat does not belong to Edge Communications.

So, what could be the options ?

Account relationship data sharing rule is perfect solution in this case without writing any code. I’ve created below video explaining how it all fits together.

Resources :

• Account Relationships & Account Relationship Data Sharing Rules